The present invention relates to a vehicle occupant-protecting apparatus, and more particularly to a vehicle occupant-protecting apparatus for reducing deceleration applied to a vehicle occupant at the time of a vehicle collision.
In recent years, various types of vehicle structures that can reduce the deceleration of portions of a vehicle body other than a passenger compartment have been proposed. For example, such reduction has been achieved by appropriately setting deformation moods in collision for the portions of the vehicle body other than the passenger compartment, and by preventing the deformation of the vehicle body in collision from extending to the passenger compartment to improve the vehicle occupant-protecting effect. See Japanese Patent Unexamined Publication No. Hei. 7-101354.
On the other hand, the deceleration of the occupant restrained in the seat by the seat belt rises when an inertia force is borne by the seat belt. Note that this inertia force is exerted on an occupant restrained in the seat by the seat belt in a forward direction in the vehicle collision. Since the spring effect of the seat belt cannot entirely be eliminated, the occupant moves by virtue of the inertia force and the deceleration of the occupant reaches its peak when the maximum extension of the seat belt is reached. The more the occupant is moved by inertia force, the higher the peak value of the occupant deceleration is increased. Accordingly, in general the value exceeds the mean deceleration of the passenger compartment of the vehicle body. Consequently, in order to reduce the impact borne by the occupant, the vehicle body deceleration needs to be adjusted such that the delay in time of the rise of the occupant deceleration relative to the vehicle body deceleration becomes as small as possible.
However, it is substantially not possible to integrally connect the occupant with the vehicle body. In particular, in the case of small cars in which the deformation stroke of the portions of the vehicle body other than the passenger compartment cannot sufficiently be provided, it is difficult to reduce further the occupant deceleration only with the conventional method for reducing the deceleration of the passenger compartment at the time of collision by setting deformation stress for the vehicle body.
The inventors of the invention disclosed herein proposed a vehicle occupant-protecting apparatus, as shown in the specification of Japanese Patent Unexamined Publication No. 2000-062556 (corresponding to U.S. Pat. No. 6,193,293). The apparatus has a seat supported on a vehicle body to be movable along a direction in which a force is applied to the vehicle body when a vehicle collides. The apparatus also has a first acceleration mechanism for applying acceleration to the seat in the same direction as that in which impact load is applied to the vehicle body and a second acceleration mechanism for applying acceleration to the seat in an opposite direction to the direction in which the impact load is applied to the vehicle body.
In the vehicle occupant-protecting apparatus so proposed, however, occupant-protecting apparatus driving rails are provided separately from seat rails for adjusting longitudinally the position of the seat. Furthermore, the first and second acceleration mechanisms are mounted on the vehicle body as constituent mechanism components independent from the seat. Consequently, the occupant-protecting apparatus itself becomes relatively larger in size and heavier in weight. Further, due to a complicated construction thereof man-hours for assembling on the production line are increased. This causes disadvantages in mounting space, cost and weight. In particular, this causes a problem that the occupant-protecting apparatus becomes difficult to be mounted on a small car light in weight and inexpensive in price.
It is an object of the present invention to solve the problems above, and to provide an improved occupant-protecting apparatus that can realize at higher levels a vehicle body compact in dimensions, light in weight and low in price while attaining the reduction of the vehicle occupant deceleration.
The object can be attained by a vehicle occupant-protecting apparatus according to a first aspect of the invention.
The apparatus comprises:
a lower rail fixed to a vehicle body;
an upper rail slidably supported on the lower rail,
a seat integrated with the upper rail and provided with a seat belt for restraining an occupant seated in the seat;
a seat slide lock mechanism for allowing the seat to be selected between a position changeable state and a fixed state,
a first acceleration member comprising a cylinder integrated with the seat for applying acceleration to the seat in the same direction as that in which impact load is applied to the vehicle body, a piston connected to the seat slide lock mechanism and piston pushing member for generating force to push out the piston from the cylinder in collision, and a second acceleration member provided inside the cylinder such that acceleration is applied to the seat via the piston in an opposite direction to the direction in which impact load is applied to the vehicle body.
According to this construction, in case of a head-on collision, for example, a higher deceleration than the vehicle deceleration can be generated in the seat in an earlier stage of impact by accelerating the seat rearward by the first acceleration member the moment a collision occurs to thereby increase the restraining force of the seat belt for restraining the forward movement of the occupant. Following this, the deceleration of the seat can be adjusted by the second acceleration member so as to substantially match the deceleration of the occupant. Thus, the increase in forward inertia force applied to the occupant at the time of collision can be cancelled so that the decelerations of the vehicle body, the seat and the occupant become equal to one another in the early stage of the impact, and since the first and second acceleration member are provided inside the cylinder which is integrated with the seat, the occupant-protecting apparatus can be placed by making use of a space, for example, under the seat, this obviating the necessity of securing a particular vacant space only for this apparatus, thereby making it possible to attain the vehicle body compact in dimensions while promoting the reduction in weight and price.
In addition, according to a second aspect of the invention, there is provided a vehicle occupant-protecting apparatus as set forth in the first aspect of the invention, wherein a selective lock member is provided between the piston and the cylinder, the selective lock member being adapted to be in an engaged state when the seat is moved to adjust its sliding position and to be put in a released state with the pushing force generated by the piston pushing member when the piston pushing member pushes out the piston. According to this construction, the sliding adjustment of the seat becomes possible in normal use.
Additionally, according to a third aspect of the invention, there is provided a vehicle occupant-protecting apparatus as set forth in the second aspect of the invention, wherein a unidirectional piston movement restriction member is provided between the piston and the cylinder, the unidirectional piston movement restriction member being adapted to be left free relative to a direction in which the piston is pushed out but to prevent the movement of the piston in an opposite direction to that in which the piston is pushed out. According to this construction, when the piston moves and the seat attempts to return forward after it has moved rearward, the vehicle body and the seat can be made integral with each other by member of the first acceleration member and the second acceleration member, thus the decelerations of the occupant and the vehicle body in the final stage of the impact being made to substantially match each other.
The above-mentioned object can also be attained by a vehicle occupant-protecting apparatus, according to the present invention comprising:
a seat for supporting at least one occupant;
lower rails fixed to a body of the vehicle;
upper rails connected to the seat of the vehicle and slidably supported on the lower rails;
an acceleration device integrated with the seat, the acceleration device including:
a cylinder;
a piston at least partially disposed within the cylinder;
a first acceleration member disposed within the cylinder and operable to apply a force to the piston to accelerate the seat in a same direction as that in which an impact load is applied to the vehicle body; and
a second acceleration member disposed within the cylinder and operable to apply a force to the piston to accelerate the seat in an opposite direction to the direction as that in which the impact load is applied to the vehicle body; and
a seat slide lock device connected to the acceleration device and operable to allow the at least one occupant to adjust and fix a sliding position of the seat.
The above-mentioned vehicle occupant-protecting apparatus, according to the present invention, may further include:
a selective lock member, the selective lock member operable to prevent piston movement when the seat is moved by the at least one occupant to adjust and fix the sliding position of the seat, and to be put in a released state allowing piston movement in response to the first acceleration member applying force to the piston.
The vehicle occupant-protecting apparatus according to the present invention, may further include:
a unidirectional piston movement restriction member operable to allow piston movement in response to the first acceleration member applying force to the piston and to prevent movement of the piston in a direction opposite to the piston movement.
The vehicle occupant-protecting apparatus according to the present invention, may further include:
a seat belt operable to restrict movement of the at least one occupant.
In the vehicle occupant-protecting apparatus according to the present invention, combustion of a propellant may be used by the first acceleration member to apply the force to the piston.
In addition, in the vehicle occupant-protecting apparatus according to the present invention, the seat slide lock device may include:
a lock plate secured to each of the lower rails, the lock plate having a plurality of lock holes;
a moveable plate attached to and bridging the lock plates, the moveable plate having moveable pawls biased towards and operable to be engaged with the plurality of lock holes; and
a frame connecting the moveable plate to the acceleration device.
Further, in the vehicle occupant-protecting apparatus according to the present invention, the second acceleration member may include a cylindrical collapsible tube.
Moreover, the vehicle occupant-protecting apparatus according to the present invention may include a collision detector operable to detect the application of the impact load to the vehicle body and provide a communication to the acceleration member.
The above-mentioned object can be achieved by a vehicle occupant protection apparatus according to the present invention comprising:
a seat supported on a vehicle body so as to be slidable in a direction in which an impact load is applied to the vehicle body as a result of a collision of the vehicle;
a first actuator operable to apply an acceleration to the seat relative to the vehicle body in a same direction as the impact load immediately after the vehicle collision, the first actuator including:
a cylinder connected to the seat;
a piston movable within the cylinder and connected to the vehicle body; and
a generator for generating a piston pushing force to push-out the piston from the cylinder during the vehicle collision; and
a second actuator disposed inside of the cylinder of the first actuator and operable to apply an acceleration to the seat in an opposite direction from the impact load.
In the vehicle occupant protection apparatus according to the present invention, the second actuator may comprise a cylindrical collapsible tube.
In addition, the vehicle occupant protection apparatus according to the present invention, the piston and the cylinder of the first actuator may be actuated by combustion of a propellant.
The vehicle occupant protection apparatus according to the present invention may include:
a selective lock member provided between the piston and the cylinder, the selective lock member being adapted to be in an engaged state when the seat is moved to adjust its sliding position and to be put in a released state in response to actuation of the first actuator.
The vehicle occupant protection apparatus according to the present invention may further include:
a unidirectional piston movement restriction member provided between the piston and the cylinder, the unidirectional piston movement restriction member being adapted to allow free movement of the piston relative to a direction in which the piston is pushed-out, and to prevent movement of the piston in an opposite direction to that in which the piston is pushed-out.
The vehicle occupant protection apparatus according to the present invention may further include:
a collision detector operable to detect the application of the impact load to the vehicle body and provide a communication to the first actuator.
The vehicle occupant protection apparatus according to the present invention may further include:
a seat slide lock device connected to the first actuator and operable to allow at least one occupant of the vehicle to adjust and fix the sliding position of the seat.
The vehicle occupant protection apparatus according to the present invention may further include:
a seat belt operable to restrict movement of at least one occupant of the vehicle.